Wave A and wave B are both traveling through the same medium - the air in the auditorium. As discussed in the Physics Rules section above, the speed at which sound waves travel through the air in the auditorium is dependent upon the properties of that air (mainly the temperature of the air). Since both waves are traveling through the same air, their speed will be the same.
The connection between speed, wavelength and frequency is stated in the Formula Fix section below. If the v in the equation is the same for both wave A and wave B, then the product of frequency and wavelength must be the same for both waves. The wave with the greatest frequency will have the shortest wavelength. In fact, the ratio of their frequencies will be inversely related to the ratio of their wavelengths.